Interest Calculator
Calculate simple or compound interest in seconds — enter the principal, rate and time to see the interest and total amount.
Interest: ₹40,000
Total amount (principal + interest): ₹1,40,000
Simple and compound interest, instantly
Interest is the cost of borrowing — or the reward for saving. Simple interest is calculated only on the original principal, while compound interest is calculated on the principal plus the interest already earned, so it grows faster over time. This tool handles both: switch the mode, enter your numbers, and choose how often interest compounds.
It is handy for fixed deposits, savings, recurring loans and exam maths problems alike. Everything is calculated locally in your browser.
Frequently asked questions
What is the simple interest formula?
Simple Interest = (Principal × Rate × Time) ÷ 100. It is calculated only on the original principal.
What is the compound interest formula?
Compound Interest amount = P × (1 + r/n)^(n×t), where P is principal, r is the annual rate (as a decimal), n is the compounding frequency per year, and t is the number of years. Interest earns interest over time.
What is the difference between simple and compound interest?
Simple interest is charged only on the principal, while compound interest is charged on the principal plus accumulated interest — so compound interest grows faster over long periods.
Is it free?
Yes — free, no sign-up, and it runs entirely in your browser.
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